package com.hmdp.service.impl;

import cn.hutool.core.bean.BeanUtil;
import com.hmdp.dto.Result;
import com.hmdp.entity.SeckillVoucher;
import com.hmdp.entity.VoucherOrder;
import com.hmdp.mapper.VoucherOrderMapper;
import com.hmdp.service.ISeckillVoucherService;
import com.hmdp.service.IVoucherOrderService;
import com.baomidou.mybatisplus.extension.service.impl.ServiceImpl;
import com.hmdp.utils.RedisIdWorker;
import com.hmdp.utils.UserHolder;
import lombok.extern.slf4j.Slf4j;
import org.redisson.api.RLock;
import org.redisson.api.RedissonClient;
import org.springframework.aop.framework.AopContext;
import org.springframework.core.io.ClassPathResource;
import org.springframework.data.redis.connection.stream.Consumer;
import org.springframework.data.redis.connection.stream.MapRecord;
import org.springframework.data.redis.connection.stream.ReadOffset;
import org.springframework.data.redis.connection.stream.StreamOffset;
import org.springframework.data.redis.connection.stream.StreamReadOptions;
import org.springframework.data.redis.core.StringRedisTemplate;
import org.springframework.data.redis.core.script.DefaultRedisScript;
import org.springframework.stereotype.Service;
import org.springframework.transaction.annotation.Transactional;

import javax.annotation.PostConstruct;
import javax.annotation.Resource;
import java.time.Duration;
import java.util.Collections;
import java.util.List;
import java.util.Map;
import java.util.concurrent.ArrayBlockingQueue;
import java.util.concurrent.BlockingQueue;
import java.util.concurrent.ExecutorService;
import java.util.concurrent.Executors;

/**
 * <p>
 *  服务实现类
 * </p>
 *
 * @author 虎哥
 * @since 2021-12-22
 */
@Slf4j
@Service
public class VoucherOrderServiceImpl extends ServiceImpl<VoucherOrderMapper, VoucherOrder> implements IVoucherOrderService {

    @Resource
    private ISeckillVoucherService seckillVoucherService;

    @Resource
    private RedisIdWorker redisIdWorker;

    @Resource
    private StringRedisTemplate stringRedisTemplate;

    @Resource
    private RedissonClient redissonClient;

    private static final DefaultRedisScript<Long> SECKILL_SCRIPT;
    static {
        SECKILL_SCRIPT = new DefaultRedisScript<>();
        SECKILL_SCRIPT.setLocation(new ClassPathResource("seckill.lua"));
        SECKILL_SCRIPT.setResultType(Long.class);
    }

    /**
     * 线程池
     */
    private static final ExecutorService SECKILL_ORDER_EXECUTOR = Executors.newSingleThreadExecutor();

    @PostConstruct // 在当前类初始化完成后执行
    private void init() {
        SECKILL_ORDER_EXECUTOR.submit(new VoucherOrderHandle());
    }
    /**
     * 阻塞队列
     */
    /*private BlockingQueue<VoucherOrder> orderTasks = new ArrayBlockingQueue<>(1024 * 1024);
    private class VoucherOrderHandle implements Runnable {
        @Override
        public void run() {
            while (true) {
                try {
                    // 1.获取队列中的订单信息
                    VoucherOrder voucherOrder = orderTasks.take();
                    // 2.创建订单
                    handleVoucherOrder(voucherOrder);
                } catch (Exception e) {
                    log.error("处理订单异常", e);
                }
            }
        }
    }*/
    private class VoucherOrderHandle implements Runnable {

        private String queueName = "stream.orders";

        @Override
        public void run() {
            while (true) {
                try {
                    // 1.获取消息队列中的订单信息 XREADGROUP GROUP g1 c1 COUNT 1 BLOCK 2000 STREAMS stream.orders >
                    List<MapRecord<String, Object, Object>> list = stringRedisTemplate.opsForStream().read(
                            Consumer.from("g1", "c1"),
                            StreamReadOptions.empty().count(1).block(Duration.ofSeconds(2)),
                            StreamOffset.create(queueName, ReadOffset.lastConsumed())
                    );
                    // 2.判断消息获取是否成功
                    if (list == null || list.isEmpty()) {
                        // 2.1.如果获取失败，说明没有消息，继续下一次循环
                        continue;
                    }

                    // 3.解析消息中的订单信息
                    MapRecord<String, Object, Object> record = list.get(0);
                    Map<Object, Object> values = record.getValue();
                    VoucherOrder voucherOrder = BeanUtil.fillBeanWithMap(values, new VoucherOrder(), true);
                    // 4.如果获取成功。创建订单
                    handleVoucherOrder(voucherOrder);
                    // 5.ACK确认 SACK stream.orders g1 id
                    stringRedisTemplate.opsForStream().acknowledge(queueName, "g1", record.getId());
                } catch (Exception e) {
                    log.error("处理订单异常", e);
                    handlePendingList();
                }
            }
        }

        private void handlePendingList() {
            while (true) {
                try {
                    // 1.获取pending-list中的订单信息 XREADGROUP GROUP g1 c1 COUNT 1 STREAMS stream.orders 0
                    List<MapRecord<String, Object, Object>> list = stringRedisTemplate.opsForStream().read(
                            Consumer.from("g1", "c1"),
                            StreamReadOptions.empty().count(1),
                            StreamOffset.create(queueName, ReadOffset.from("0"))
                    );
                    // 2.判断消息获取是否成功
                    if (list == null || list.isEmpty()) {
                        // 2.1.如果获取失败，说明pending-list中没有异常消息，结束循环
                        break;
                    }

                    // 3.解析消息中的订单信息
                    MapRecord<String, Object, Object> record = list.get(0);
                    Map<Object, Object> values = record.getValue();
                    VoucherOrder voucherOrder = BeanUtil.fillBeanWithMap(values, new VoucherOrder(), true);
                    // 4.如果获取成功。创建订单
                    handleVoucherOrder(voucherOrder);
                    // 5.ACK确认 SACK stream.orders g1 id
                    stringRedisTemplate.opsForStream().acknowledge(queueName, "g1", record.getId());
                } catch (Exception e) {
                    log.error("处理pending-list订单异常", e);
                    try {
                        Thread.sleep(20);
                    } catch (InterruptedException ex) {
                        ex.printStackTrace();
                    }
                }
            }
        }
    }

    private void handleVoucherOrder(VoucherOrder voucherOrder) {
        // 1.获取用户
        Long userId = voucherOrder.getUserId();
        // 2.创建锁对象
        RLock lock = redissonClient.getLock("lock:order:" + userId);
        // 3.获取锁
        boolean isLock = lock.tryLock();
        // 4.判断是否获取锁成功
        if (!isLock) {
            // 获取锁失败，返回错误信息或重试
            log.error("不允许重复下单");
            return;
        }
        // 获取锁成功
        try {
            // 获取代理对象（事务）
            proxy.createVoucherOrder(voucherOrder);
        } finally {
            // 释放锁
            lock.unlock();
        }
    }
    private IVoucherOrderService proxy;

    @Override
    public Result seckillVoucher(Long voucherId) {
        // 获取用户
        Long userId = UserHolder.getUser().getId();
        // 获取订单id
        long orderId = redisIdWorker.nextId("order");
        // 1.执行lua脚本
        Long result = stringRedisTemplate.execute(
                SECKILL_SCRIPT,
                Collections.emptyList(),
                voucherId.toString(), userId.toString(),
                String.valueOf(orderId)
        );
        // 2.判断结果是否为0
        int r = result.intValue();
        if (r != 0) {
            // 2.1.不为0.代表没有购买资格
            return Result.fail(r == 1 ? "库存不足" : "不能重复下单");
        }

        // 3.获取代理对象
        proxy = (IVoucherOrderService) AopContext.currentProxy();
        // 4.返回订单id
        return Result.ok(orderId);
    }

    //@Override
    //public Result seckillVoucher(Long voucherId) {
    //    // 获取用户
    //    Long userId = UserHolder.getUser().getId();
    //    // 1.执行lua脚本
    //    Long result = stringRedisTemplate.execute(
    //            SECKILL_SCRIPT,
    //            Collections.emptyList(),
    //            voucherId.toString(), userId.toString()
    //    );
    //    // 2.判断结果是否为0
    //    int r = result.intValue();
    //    if (r != 0) {
    //        // 2.1.不为0.代表没有购买资格
    //        return Result.fail(r == 1 ? "库存不足" : "不能重复下单");
    //    }
    //
    //    // 2.2.为0，代表有购买资格，把下单的信息保存到阻塞队列
    //    VoucherOrder voucherOrder = new VoucherOrder();
    //    // 2.3.订单id
    //    long orderId = redisIdWorker.nextId("order");
    //    voucherOrder.setId(orderId);
    //    // 2.4.用户id
    //    voucherOrder.setUserId(userId);
    //    // 2.5.代金券id
    //    voucherOrder.setVoucherId(voucherId);
    //    // 2.6.放入阻塞队列
    //    orderTasks.add(voucherOrder);
    //    // 3.获取代理对象
    //    proxy = (IVoucherOrderService) AopContext.currentProxy();
    //    // 4.返回订单id
    //    return Result.ok(orderId);
    //}

    //@Override
    //public Result seckillVoucher(Long voucherId) {
    //    // 1.查询优惠券
    //    SeckillVoucher voucher = seckillVoucherService.getById(voucherId);
    //    // 2.判断秒杀是否开始
    //    if (voucher.getBeginTime().isAfter(LocalDateTime.now())) {
    //        // 尚未开始
    //        return Result.fail("秒杀尚未开始！");
    //    }
    //    // 3.判断秒杀是否已经结束
    //    if (voucher.getEndTime().isBefore(LocalDateTime.now())) {
    //        // 尚未开始
    //        return Result.fail("秒杀已经结束！");
    //    }
    //    // 4.判断库存是否充足
    //    if (voucher.getStock() < 1) {
    //        // 库存不足
    //        return Result.fail("库存不足！");
    //    }
    //    Long userId = UserHolder.getUser().getId();
    //
    //    //synchronized(userId.toString().intern()) {
    //    //    // 获取代理对象（事务）
    //    //    IVoucherOrderService proxy = (IVoucherOrderService) AopContext.currentProxy();
    //    //    return proxy.createVoucherOrder(voucherId);
    //    //}
    //    // 创建锁对象
    //    //SimpleRedisLock lock = new SimpleRedisLock("order:" + userId, stringRedisTemplate);
    //    RLock lock = redissonClient.getLock("lock:order:" + userId);
    //    // 获取锁
    //    boolean isLock = lock.tryLock();
    //    // 判断是否获取锁成功
    //    if (!isLock) {
    //        // 获取锁失败，返回错误信息或重试
    //        return Result.fail("不允许重复下单");
    //    }
    //    // 获取锁成功
    //    try {
    //        // 获取代理对象（事务）
    //        IVoucherOrderService proxy = (IVoucherOrderService) AopContext.currentProxy();
    //        return proxy.createVoucherOrder(voucherId);
    //    } finally {
    //        // 释放锁
    //        lock.unlock();
    //    }
    //}
    @Transactional
    public void createVoucherOrder(VoucherOrder voucherOrder) {
        // 5.一人一单
        // 5.1.查询订单
        Long userId = voucherOrder.getUserId();
        int count = lambdaQuery().eq(VoucherOrder::getUserId, userId).eq(VoucherOrder::getVoucherId, voucherOrder.getVoucherId()).count();
        // 5.2.判断是否存在
        if (count > 0) {
            // 存在，用户已经购买过了
            log.error("该用户已经购买过一次了！");
            return;
        }
        // 6.扣减库存
        boolean success = seckillVoucherService.lambdaUpdate()
                .setSql("stock = stock - 1") // set stock = stock - 1
                .eq(SeckillVoucher::getVoucherId, voucherOrder.getVoucherId()) // where id = ? and stock = ?
                .gt(SeckillVoucher::getStock, 0)
                .update();
        if (!success) {
            // 扣减失败
            log.error("库存不足！");
            return;
        }
        // 7.创建订单
        save(voucherOrder);
    }
}
